smbg chien-wen chou md

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SMBG Chien-Wen Chou MD. Endocrinology & Metabolism Divisio n Chi-Mei Medical Center 8 Jul 2005

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Page 1: SMBG Chien-Wen Chou MD

SMBG

Chien-Wen Chou MD.Endocrinology & Metabolism Division

Chi-Mei Medical Center8 Jul 2005

Page 2: SMBG Chien-Wen Chou MD

Daily Self-Monitoring

• To detect asymptomatic hypoglycemia

• To guide patient and provider behavior toward reaching blood glucose goals

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Introduction

• A strict glycemic control reduces the risk of the development of micro- and macrovascular complications .

• In the U.K. Prospective Diabetes Study, each 1% reduction in HbA1c was associated with a 37% decrease in risk for microvascular complications and a 21% decrease in risk for any end point or death related to diabetes.

• In clinical practice, a 3-monthly visit to the general practitioner is recommended for the assessment of glycemic control.

• There is now much debate on the effectiveness of self-monitoring of blood glucose (SMBG) as a tool in the self-management of diabetic patients.

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Introduction

• SMBG aims at collecting information on blood glucose levels at different time points during the day and allows for the timely identification of high levels.

• SMBG has proven effective for patients with type 1 diabetes and patients with type 2 diabetes who are using insulin because the information about a patient’s glucose level is useful to refine and adjust insulin dosages, resulting in an improved glycemic control.

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DCCT

• A total of 1441 patients with IDDM -- 726 with no retinopathy at base line (the primary-prevention cohort) and 715 with mild retinopathy (the secondary-intervention cohort)

• were randomly assigned to intensive therapy administered either with an external insulin pump or by three or more daily insulin injections and guided by frequent blood glucose monitoring

• or to conventional therapy with one or two daily insulin injections.

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Figure 1. Measurements of Glycosylated Hemoglobin and Blood Glucose in Patients with IDDM Receiving Intensive or Conventional Therapy.

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Frequency of Blood Glucose Monitoring in Relation to Glycemic Control in Patients With Typ

e 2 Diabetes

Maureen I. Harris, PHD, MPH Diabetes Care

24:979-982, 2001

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NHANES III (Sep 1988 to Oct 1994)

• 29% treated with insulins

• 65% treated with oral agents

• 80% treated with diet alone had never monitored or less than once per month

• Self-monitoring at least once per day 39% of those taking insulin

• 5-6% of those treated with oral agents or diet alone

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NHANES III (Sep 1988 to Oct 1994)

• Patients who tested their blood glucose increased with an increasing HbA1c value

• Examined by diabetes therapy category, little relationship between HbA1c value and the proportion testing at least once per day or the proportion testing at least once per week

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Table 1 — HbA1c values and frequency of blood glucose self-monitoring by patients with type 2 diabetes, according to diabetes

treatment

All patients Insulin Oral agents

Diet alone

Patient distribution (%) 100.0 27.3 45.5 27.2

Mean HbA1c value* 7.64 8.29 8.04 6.37

Proportion with HbA1c  8 (%) 37.1 51.4 42.2 14.9

Blood glucose self-monitoring (%)

 Never or <1 time per month 58.9 28.7 65.2 79.7

 1–3 times per month 8.5 11.1 9.2 4.6

 1–6 times per week 18.0 21.1 21.0 9.2

   1 time per day 14.6 39.1 4.6 6.5

The upper limit of normal for HbA1c in the assay system is 6.1%, defined as the mean + 2 SDs (5.27 + 0.86%) for the group of people with fasting plasma glucose <110 mg/dl and 2-h postchallenge glucose <140 mg/dl.

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NHANES III (Sep 1988 to Oct 1994)

• A cross-sectional study• Medicare reimbursement the cost of blood

glucose monitors and test strips for monitors only for patients with insulin

• In 1998, this policy was changes to reimburse patients for these items, regardless of whether the patient is treated with insulin

• 1997-1999, the proportion of all diabetic patients who self-monitored at least once per day was 44%

Page 14: SMBG Chien-Wen Chou MD

Frequency of Blood Glucose Monitoring in Relation to Glycemic Control in Patients With Typ

e 2 Diabetes

Diabetes Care

25:245-246, 2002

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ISIS Group (Oct 1996 to Sep 1999)

• >3000 clinic visits of 228 patients with type 2 diabetes

• Average HbA1c decreased by 0.8• 21% of patients were regular SMBG performers• 70% of these patients had HbA1c <= 8• For the 42%of patients who were irregular

SMBG performers• 37% of patients not monitoring, only 18 and 22%

respectively, had HbA1c <= 8

Page 16: SMBG Chien-Wen Chou MD

Table 1— Influence of health care providers’ contact on clinical effect of SMBG

HbA1c  <= 8

>8

Regular SMBG peformers (21%) 70% 30%

Irregular SMBG performers (42%) 18% 82%

Not monitored (37%) 22% 78%

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Self-Monitoring of Blood Glucose in Patients With Type 2 Diabetes Who Are Not Using Insulin

Diabetes Care 28:1510-1517, 2005

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Conclusion

• In our review, six randomized controlled trials could be included to evaluate the effects of SMBG in patients with type 2 diabetes who are not using insulin.

• The overall effect of SMBG was a statistically significant decrease of 0.39% in HbA1c compared with the control groups.

• This is considered clinically relevant. • Based on the U.K. Prospective Diabetes Study,

a decrease of 0.39% in HbA1c is expected to reduce risk of microvascular complications by 14%

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Variability in response to SMBG

• Multiple factors impact upon an outcome such as A1C. • As an example, baseline A1C values may reflect importa

nt clinical situations that impact design, particularly when disproportionately high or low.

• Patients with A1C close to normal may not show much change with either SMBG or usual care, and inclusion of a large number of such patients in studies may minimize differences between groups.

• Very poor glycemic control may also be associated with little benefit of SMBG.

• In type 2 diabetic patients with high A1C on maximal dose and number of oral agents, insulin therapy may be the only solution to improve glycemic control and SMBG would be unlikely to influence the outcome.

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Variability in response to SMBG

• The number of oral agents per patient was not clearly described in many of the six studies, or if reported, subjects on such a regimen were not always equally divided between intervention and control groups.

• Finally, the actual number of SMBG measurements performed in the course of the study or their relationship to meals is not always reported

• understanding effectiveness requires that compliance with SMBG frequency and timing also be documented and reported.

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SMBG Use and Frequency

• Insulin-treated patients should monitor their blood glucose level varies from person to person

• At least four times a day. • Most commonly fasting, before meals, and befor

e bed• In addition, patients using insulin can benefit by

obtaining postprandial blood glucose readings to help them more accurately adjust their insulin regimen

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SMBG Use and Frequency

• For patients with type 2 diabetes, optimal SMBG frequency varies depending on the pharmaceutical regimen and whether patients are in an adjustment phase or at their target for glycemic control

• If a patient is on a stable oral regimen with HbA1c concentration within the target range, infrequent SMBG monitoring is appropriate.

• In such cases, patients can use SMBG data as biofeedback at times of increased stress or changes in diet or physical activity.

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SMBG Use and Frequency

• For patients whose diabetes is out of control or for those having medication initiated, however, SMBG data can be helpful in creating or modifying the diabetes management regimen.

• Persistent fasting hyperglycemia, for example, might indicate excessive hepatic glucose output, and patients experiencing this problem might derive benefit from using metformin (Glucophage), which has been shown to decrease nocturnal hepatic glucose output.

• Additionally, patients with persistent postprandial hyperglycemia might derive benefit from taking a short-acting oral agent with meals to either decrease carbohydrate absorption (i.e., an alpha-glucosidase inhibiter such as acarbose [Precose] or miglitol [Glyset]) or stimulate insulin secretion at the time of the meal (i.e., repaglinide [Prandin] or nateglinide [Starlix]).

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SMBG Use and Frequency

• People with type 2 diabetes who use insulin should perform SMBG at least four times per week, including at least two fasting and two postprandial values.

• Additional measurements at bedtime and before meals can also be obtained.

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